1. Field of the Invention
The present invention relates to a digital camera, and more particularly, to a digital camera capable of cleaning its image sensor or an optical component attached to the image sensor.
2. Description of the Related Art
A conventional digital camera may have a detachable lens. A subject image entering through the lens is directed to an optical finder through a return mirror. The user finds the subject image through the optical finder. When the user pushes the shutter release button, the return mirror is raised, the shutter curtain opens, and light from the subject arrives at the image sensor. The image sensor produces the subject image as an electrical signal, and outputs it as image data. Then, the shutter curtain is closed. Shutter operation includes raising the return mirror and opening and closing the shutter curtain. The image data is processed and stored on a recording medium as an image file.
The image sensor is provided in a mirror box of a digital camera with movable elements such as a shutter curtain and a return mirror. These movable elements move whenever a photograph is taken, and graze the supports of the movable elements, creating dust particles between the supports and the movable elements. Additionally, in the case of a digital camera having a detachable lens, dust particles may enter the mirror box when the lens is removed. These dust particles may become attached to the image sensor and block light arriving at the imaging sensor. The dust particles may thereby reduce the quality of a photographed image.
To solve this problem, Japanese Unexamined Patent Publication (KOKAI) No. 2005-341381 discloses that pixels having low output value in an image signal are detected, and the data for those pixels is corrected under the assumption that dust particles are attached at those pixel locations.
However, according to conventional constructions which locate dust particles, the location of dust particles on the low-pass filter may change over time or after many shutter operations. The user cannot reliably pinpoint the location of dust particles on the low-pass filter in such a situation.